Civil Engineering - Concrete Technology

16. 

The factor which affects workability, is

A. water content and its temperature
B. shape and size of the aggregates
C. grading and surface textures of the aggregates
D. air entraining agents
E. all the above.

Answer: Option E

Explanation:

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17. 

The cement whose strength is a little lower than the ordinary cement during the first three months but attains afterwards the same strength, is known as

A. low-heat Portland cement
B. rapid hardening Portland cement
C. Portland blast slag cement
D. Portland pozzolana cement
E. none of these.

Answer: Option A

Explanation:

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18. 

Pick up the correct statement from the following:

A. Sand stones may be divided into calcareous, siliceous and ferrugineous sand stones
B. Concrete using sand stones, cracks due to excessive shrinkage
C. Very hard and close grained crystallined lime stones are suitable aggregates but provide low strength
D. Broken bricks produce a concrete having good fire resisting qualities
E. All the above.

Answer: Option E

Explanation:

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19. 

Pick up the correct statement from the following:

A. Water enables chemical reaction to take place with cement
B. Water lubricates the mixture of gravel, sand and cement
C. Only a small quantity of water is required for hydration of cement
D. Strength of concrete structure largely depends upon its workability
E. All the above.

Answer: Option E

Explanation:

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20. 

Pick up the incorrect statement applicable to the field test of good cement.

A. When one thrusts one's hand into a bag of cement, one should feel warm
B. The colour of the cement is bluish
C. A handful of cement thrown into a bucket of water should sink immediately
D. By rubbing cement in between fingers, one should feed rough
E. All the above.

Answer: Option E

Explanation:

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